Sudoku Solver
Enter your Sudoku puzzle and solve it instantly
Click a cell and type numbers to enter values
Free Sudoku Solver - Solve Any Puzzle Instantly
Enter any Sudoku puzzle and get the solution in seconds. Works with 4x4, 6x6, 9x9, and 16x16 grids. Perfect for checking your work or learning solving techniques.
Solve Any Sudoku Puzzle in Seconds
Instant Solver
Our advanced backtracking algorithm can solve any valid Sudoku puzzle almost instantly. Enter the numbers from your puzzle, click solve, and see the complete solution. Works with all standard grid sizes from 4x4 to 16x16.
Try the Solver
Real-time Conflict Detection and Error Checking
Smart Validation
As you enter numbers, our solver highlights conflicts in real-time. If a puzzle has no solution or multiple solutions, you'll know immediately. Perfect for verifying newspaper puzzles or checking your own work.
Check Your Puzzle
How to Use the Sudoku Solver
Solve any Sudoku puzzle in three simple steps. Enter the numbers, click solve, and see the answer instantly.
Select Your Grid Size
Step 1
Choose 4x4, 6x6, 9x9, or 16x16 to match your puzzle.
Enter Your Puzzle
Step 2
Click cells and type the given numbers from your Sudoku puzzle.
Click Solve
Step 3
Press the Solve button and see the complete solution instantly.
Why Use Our Sudoku Solver?
The fastest way to solve any puzzle
Instant Solutions
Our algorithm solves even the hardest puzzles in milliseconds.
- Optimized backtracking algorithm
- Handles all grid sizes
- Works offline in your browser
Verify Your Work
Check if your solution is correct or if a puzzle is solvable.
- Validate newspaper puzzles
- Check your own solutions
- Detect unsolvable puzzles
Learn Techniques
Study solutions to improve your own solving skills.
- See correct placements
- Understand puzzle logic
- Practice with verification
Trusted by Puzzle Enthusiasts Worldwide
See how our solver helps people learn and verify Sudoku solutions.
Emily Park
Math Student
I use this to check my homework puzzles. When I get stuck, I can see the solution and understand where I went wrong. It's helped me improve my solving techniques.
Robert Kim
Puzzle Enthusiast
Sometimes newspaper puzzles have typos. This solver quickly tells me if a puzzle is valid or has no solution. Saves me from wasting time on broken puzzles.
Dr. Sarah Chen
Computer Science Professor
I use this as a teaching example for backtracking algorithms. Students can see how constraint propagation works in real-time. Great educational tool.
Sudoku Solver FAQs
Common questions about solving Sudoku puzzles
The solver uses a backtracking algorithm. It tries placing numbers in empty cells, checking constraints (row, column, box uniqueness), and backtracks when it hits a dead end. This guarantees finding a solution if one exists.
If the puzzle has conflicting numbers or is mathematically impossible to solve, you'll see a "No solution exists" message. Check for typos in your input or verify that the original puzzle is valid.
The solver finds and displays one valid solution. Proper Sudoku puzzles should have exactly one unique solution. If your puzzle has multiple solutions, it means some numbers are missing from the original.
We support 4x4 (2x2 boxes), 6x6 (2x3 boxes), 9x9 (3x3 boxes - the classic size), and 16x16 (4x4 boxes) grids. Select the matching size before entering your puzzle.
Most 9x9 puzzles solve in under 50 milliseconds. Even the hardest puzzles with minimal givens typically solve in under a second. The 16x16 grid may take slightly longer but is still very fast.